This study aimed to find out the effectiveness of Kahoot and Quizizz, mobile game-based learning platforms, on students’ academic achievement and engagement. In addition, the study also investigated students’ perceptions towards using these platforms in grammar learning. The participants were the English-majored freshmen at Tay Do University. For the instruments, the researcher used pre-tests and post-tests to assess students’ academic achievement, and classroom observations to examine students’ engagement. Questionnaires and interviews were also employed to explore students’ perceptions towards utilizing these platforms for grammar instruction. The study revealed improvements in student grammar knowledge, increased engagement, and positive perceptions towards learning grammar with Kahoot and Quizizz.This study aimed to find out the effectiveness of Kahoot and Quizizz, mobile game-based learning platforms, on students’ academic achievement and engagement. In addition, the study also investigated students’ perceptions towards using these platforms in grammar learning. The participants were the English-majored freshmen at Tay Do University. For the instruments, the researcher used pre-tests and post-tests to assess students’ academic achievement, and classroom observations to examine students’ engagement. Questionnaires and interviews were also employed to explore students’ perceptions towards utilizing these platforms for grammar instruction. The study revealed improvements in student grammar knowledge, increased engagement, and positive perceptions towards learning grammar with Kahoot and Quizizz.